# Update by query to rename fields
**URL:** https://discuss.elastic.co/t/update-by-query-to-rename-fields/120552
**Category:** Elasticsearch
**Created:** [February 20, 2018, 3:43am UTC](https://discuss.elastic.co/t/update-by-query-to-rename-fields/120552 "2018-02-20T03:43:25Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@seanziee](https://discuss.elastic.co/u/seanziee)
#### Post date: [February 20, 2018, 3:43am UTC](https://discuss.elastic.co/t/update-by-query-to-rename-fields/120552/1 "2018-02-20T03:43:25Z")
Hi, I've looked all over for how to rename a field and everyone mentions doing a reindex. But isn't a script just as if not more effective (if you don't want to reindex). I just want to make sure I'm not missing something vital here because this seems like a perfectly good solution!
```auto
POST /indexName/_update_by_query
{
"script": {
"source":"ctx._source.newField =ctx._source.oldField"
},
"query": { "match_all":{} }
}
POST /indexName/_update_by_query
{
"script": {
"inline": "ctx._source.remove(\"oldField\")"
},
"query": { "match_all":{} }
}
```
Or even
```auto
POST /indexName/_update_by_query
{
"script": {
"source":"ctx._source.newField =ctx._source.remove(\"oldField\")"
},
"query": { "match_all":{} }
}
```
---
### Author:  [@val](https://discuss.elastic.co/u/val)
#### Post date: [February 20, 2018, 4:14am UTC](https://discuss.elastic.co/t/update-by-query-to-rename-fields/120552/2 "2018-02-20T04:14:54Z")
Yes, that will work, however, the field definition will not be removed from your mapping, i.e. you will continue to see `oldField` in your mapping.
Whereas with reindexing you can keep your mapping clean, i.e. in the new index, `oldField` will not be present anymore.
Pragmatism is in order here. If you just need to change one field name and/or your index seems to big to reindex, definitely go with update by query. However, if renaming a field is a frequent operation that you're doing, you might want to reindex in order to keep your mapping clean.
---
### Author:  [@seanziee](https://discuss.elastic.co/u/seanziee)
#### Post date: [February 20, 2018, 4:38am UTC](https://discuss.elastic.co/t/update-by-query-to-rename-fields/120552/3 "2018-02-20T04:38:09Z")
Ok thanks for the heads up!
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [March 20, 2018, 4:38am UTC](https://discuss.elastic.co/t/update-by-query-to-rename-fields/120552/4 "2018-03-20T04:38:11Z")
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